Heretofore, front-passenger seat airbag devices to be installed at instrument panels of automobiles have been known, for example. Such an airbag device includes an airbag having: an inflator configured to supply a gas; and a sac-like airbag main body housed while being folded in a predetermined shape. In a collision of an automobile, for example, the inflator supplies a gas to the airbag, and the airbag main body inflates and deploys in front of the passenger seated on the front-passenger seat, thereby mitigating the impact on the passenger.
There is a known configuration for such an airbag, which includes: lids covering, for example, discharge holes formed respectively in two lateral surfaces, that is, vent holes; and tethers serving as connection members each having one end that is connected to a corresponding one of the lids and a second end that is connected to a rear surface side of a center portion of a passenger restraining surface for restraining the passenger. In this configuration, the lids pulled by the tethers according to how the passenger is restrained switch between the opening and closing of the vent holes, thereby adjusting the internal pressure of the airbag main body. In addition, the robustness in misalignment of the restraint position at the passenger restraining surface is improved by partially intersecting the tethers (see, e.g., Patent Literature (hereinafter, referred to as “PTL”) 1.